System and method for dual-channel optical phase modulation mm wave generation and remote vibration provision in mm wave optical transmission system

Abstract

The present invention relates to a system for generating a two-way light phase modulation millimeter wave and providing remote local oscillator in a millimeter wave optical fiber transmission system and a method thereof. The system comprises a center station and a base station. The center station is composed of a laser, two polarization controllers, a double-electrode Mach-Zehnder modulator, a microwave difference power amplifier, a light intensity modulator, an optical fiber amplifier and the like. The base station is composed of a photodetector, a front low-noise amplifier, a power divider,two band-pass filters, two millimeter wave amplifier and a millimeter wave transmitting antennae. In the method, a single mode laser is divided into two routes at the center station. Two opposite-phase 5GHz cosine microwave signals are used for phase modulating with large modulation index to the two routes of optical wave. The two routes of optical waves are overlapped. The phase variation of theoptical wave is switched to a strength variation through a FM-IM effect. The strength variation comprises a microwave signal and a high order component thereof. The millimeter wave signal is obtainedby extracting the high order harmonic. Then the optical fiber is executed with a strength modulation with a 2GHz BPSK signal and a mode of regulated subcarrier through a light intensity modulator. A 40GHz millimeter wave remote reference local oscillator and a 38GHz BPSK signal are obtained at the base station. The number of optical frequency doubling gets to 8, and the speed of baseband data transmission gets to 200Mbps.

Description

Technical field: [0001] The present invention relates to a system and method for generating and providing a remote local oscillator in a millimeter-wave optical fiber transmission (RoF) system with dual-path optical phase modulation. The core idea is to divide the single-mode laser into two paths at the central station, and use two anti-phase 5GHz cosine microwave signals to modulate the phase of the two paths of light waves with a large modulation index, and then superimpose the two light waves to generate FM- The IM effect converts the phase change of the light wave into an intensity change. The intensity change contains the microwave signal and its high-order harmonic components, and the high-order harmonics are extracted to obtain a millimeter wave carrier. Then, the 2GHz BPSK signal is used to modulate the intensity of the light wave in the form of a modulated subcarrier, and the 40GHz millimeter wave remote reference local oscillator and the 38GHz BPSK signal can be obta...

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Problems solved by technology

[0009] The purpose of the present invention is to solve the problems of complex system, high cost and difficult maintenance in the existing millimeter wave generation technology, and propose a system and method

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